Traumatic rupture of the superior oblique muscle is rare. We report a case of a 54-year-old man injured by the metal hook of a hanger, resulting in a rupture of the superior oblique muscle tendon. He complained of torsional diplopia when in the primary position. The distal margin of the superior oblique muscle was reattached to sclera 5 and 9 mm apart from the medial insertion of the superior rectus muscle. One week after the operation, torsional diplopia disappeared. However, a 4-prism diopter ipsilateral hypertropia was observed. Three months later, hypertropia gradually increased to 20 prism dioptors and the second operation was done to correct vertical diplopia.